1. Field of the Invention
This invention relates to a method for harvesting latent energy and nonvaporous water from atmospheric air.
2. Background Art
There has been an increasing interest in environmental energy harvesting. The most well-developed methodologies focus on wind energy, solar energy, and the energy of water flowing under the influence of gravity. A number of strategies have also been developed for harvesting latent energy from atmospheric air. Some of these strategies depend on added water vapor and vertically decreasing atmospheric pressure to stimulate an upward movement of air. Such air within an enclosed, vertical conduit is forced by a pressure differential to rise through a wind turbine driving an electric generator to extract energy. In another strategy, air at the conduit base is warmed; and warm water vapor is added. The vapor is assumed to condense as air rises within the enclosed conduit, warming the air and enhancing upward motion. The condensed water is removed in an upper region of the conduit. Other strategies seek similar results but depend on evaporating liquid water into air, thus cooling the air and stimulating the air to move downwardly rather than upwardly. This process finds useful application, for example, in cleaning pollution from industrial stacks, where there is no interest in energy harvesting. Another strategy has liquid water pumped to a high elevation and sprayed into environmental air at that level to cool the air by evaporation. The evaporative air cooling is performed within a conduit that extends from a high to a low altitude, and kinetic energy of the resulting downdraft of air is extracted by a wind turbine driving an electric generator.
Still other strategies do not depend on pressure-altitude differences but disclose machine means for harvesting energy from water vapor provided by a boiler. At least one other strategy uses a flash evaporator to produce steam and a steam-driven turbogenerator to produce energy, and another depends on elaborate machine means to harvest energy by liquefying air itself rather than merely liquefying water vapor.
A number of strategies disclose the removal of condensed liquid water from an air-water mixture contained within a closed volume. One discloses means to control the formation of condensate into liquid droplets using a condensing surface of inverted circular cones attached to a metal plate. Another discloses means for collecting water blown off a cooling coil by high velocity air, improving such collection by coils used in low-fluid-velocity water collection systems. Yet another discloses the use of charged aerosol sources powered directly by the wind. The means comprise a large area electrode screen, which emits charged water droplets into a wind stream as a wind-electric power transducer. Still another discloses means for harvesting water from air that involve an isothermal compression to a saturated state that requires means to remove energy from the process to maintain the isothermal compression. In contrast, the process of the present invention adiabatically decompresses, with no exchange of energy with an external environment, a controlled volume of atmospheric air to a pressure at which resident water vapor reaches a saturated state.